Effect of short thermal treatment on microstructure evolution and superelasticity in Ti-20Zr-3Mo-3Sn alloy

In this work, the effect of short thermal treatment (700 degrees C, 800 degrees C, 900 degrees C for 5 min) on microstructure evolution and superelasticity is investigated by cyclic tensile tests, X-ray diffraction (XRD) and electron back-scattered diffraction (EBSD) in Ti-20Zr-3Mo-3Sn (Ti2033, at%) alloy. All the samples indicate single beta phase after thermal treatment, and the recovery strain decreases from 3.3 % at 700 degrees C to 2.5 % at 900 degrees C. Meanwhile, the heat treated specimens at 700 degrees C and 800 degrees C display the same {121}< 101 >(beta) recrystallization texture, it however changes into {101}< 001 >(beta) texture at 900 degrees C. In addition, all the three samples reveal stable maximum recovery strain after 4 % of applied strain through short thermal treatment independent of the recrystallized texture, which was never reported before. Our study gives a good guidance to obtain ideal superelastic performance for metastable beta titanium alloys.